Cells: Antibodies in medicine Flashcards
What are monoclonal antibodies
They are antibodies produced from a single group of genetically identical B-cells (plasma cells)
How are monoclonal antibodies useful for both treating illnesses and in medical diagnosis
- You can make monoclonal antibodies bind to anything you want
Outline how monoclonal antibodies are useful anti-cancer drugs
- Cancer cells have antigens called tumour markers that are not found on normal body cells
- Monoclonal antibodies can be made that will bind to the tumour markers AND you can also attach anti-cancer drugs to these antibodies
- When the antibodies come into contact with the cancer cells they will bind to the tumour markers AND it will only accumulate where the cancer cells are
- The side effects of an antibody-based
drug are lower than other drugs because they accumulate near specific cells.
What hormones do pregnancy tests detect
hCG
Outline how monoclonal antibodies are useful for pregnancy tests
- Pregnancy tests detect the hormone human chorionic gonadotropin (hCG) that’s found in the urine of pregnant women
- The application area contains antibodies that are complementary to the hCG protein, bound to a coloured bead (blue).
*When urine is applied to the application area any hCG will bind to the antibody on the beads, forming an antigen-antibody complex.
- The urine moves up the stick to the test strip, carrying any beads with it
*The test strip contains antibodies to hCG that are stuck in place
(immobilised).
- If there is hCG present the test strip turns blue because the immobilised antibody binds to any hCG — concentrating the hCG-antibody complex
with the blue beads attached. - If no hCG is present, the beads will pass
through the test area without binding to anything, and so it won’t go blue.
What does the ELISA test stand for
The ‘enzyme-linked immunosorbent assay
What is the ELISA test
It is a test that allows you to see if a patient has any antibodies to a certain antigen OR any antigen to a certain antibody
What can the ELISA test be used for
It can be used in medical diagnosis to test for pathogenic infections, allergies AND anything you can make an antibody for
Give example of things ELISA can test for
- HIV infection
- Nuts or lactose (allergies)
What are the two main types of ELISA tests and the antibodies they use
- Direct ELISA tests: uses a single antibody that is complementary to the antigen being tested for
- Indirect ELISA tests: uses two different antibodies (known as primary and secondary antibodies)
Outline indirect ELISA being used to test if a patient possesses the antibodies to HIV
- HIV antigen is bound to bottom of a well in a well plate
- A sample of a person’s plasma is added to the well. If there are HIV specific antibodies they will bind to the HIV antigen. The well is washed out to remove other antigens and antibodies
- Another antibody that has an enzyme attached to it is added. This antibody binds to the HIV antibody. The well is washed again
- A solution is added to the well, containing a substrate, which can react with the enzyme attached to the secondary antibody - This reaction will produce a coloured product
What happens during an direct ELISA test
- An enzyme is attached to antibodies
- When this enzyme reacts with a certain substrate, a coloured product is formed, causing the solution in the reaction vessel to change colour
- If a colour change occurs, this shows that the antigen or antibody of interest is present in the sample being tested (e.g. blood plasma)
State the ethical issues of using monoclonal antibodies
- Animals are used to produce the cells from which the monoclonal antibodies are produced
